ixgbe: protect ring accesses with READ- and WRITE_ONCE

READ_ONCE should be used when reading rings prior to accessing the
statistics pointer. Introduce this as well as the corresponding WRITE_ONCE
usage when allocating and freeing the rings, to ensure protected access.

Signed-off-by: Ciara Loftus <ciara.loftus@intel.com>
Tested-by: Andrew Bowers <andrewx.bowers@intel.com>
Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>

diff --git a/drivers/net/ethernet/intel/ixgbe/ixgbe_lib.c b/drivers/net/ethernet/intel/ixgbe/ixgbe_lib.c
index fd9f5d4..2e35c57 100644 (file)
--- a/drivers/net/ethernet/intel/ixgbe/ixgbe_lib.c
+++ b/drivers/net/ethernet/intel/ixgbe/ixgbe_lib.c
@@ -921,7 +921,7 @@ static int ixgbe_alloc_q_vector(struct ixgbe_adapter *adapter,
                ring->queue_index = txr_idx;
 
                /* assign ring to adapter */
-               adapter->tx_ring[txr_idx] = ring;
+               WRITE_ONCE(adapter->tx_ring[txr_idx], ring);
 
                /* update count and index */
                txr_count--;
@@ -948,7 +948,7 @@ static int ixgbe_alloc_q_vector(struct ixgbe_adapter *adapter,
                set_ring_xdp(ring);
 
                /* assign ring to adapter */
-               adapter->xdp_ring[xdp_idx] = ring;
+               WRITE_ONCE(adapter->xdp_ring[xdp_idx], ring);
 
                /* update count and index */
                xdp_count--;
@@ -991,7 +991,7 @@ static int ixgbe_alloc_q_vector(struct ixgbe_adapter *adapter,
                ring->queue_index = rxr_idx;
 
                /* assign ring to adapter */
-               adapter->rx_ring[rxr_idx] = ring;
+               WRITE_ONCE(adapter->rx_ring[rxr_idx], ring);
 
                /* update count and index */
                rxr_count--;
@@ -1020,13 +1020,13 @@ static void ixgbe_free_q_vector(struct ixgbe_adapter *adapter, int v_idx)
 
        ixgbe_for_each_ring(ring, q_vector->tx) {
                if (ring_is_xdp(ring))
-                       adapter->xdp_ring[ring->queue_index] = NULL;
+                       WRITE_ONCE(adapter->xdp_ring[ring->queue_index], NULL);
                else
-                       adapter->tx_ring[ring->queue_index] = NULL;
+                       WRITE_ONCE(adapter->tx_ring[ring->queue_index], NULL);
        }
 
        ixgbe_for_each_ring(ring, q_vector->rx)
-               adapter->rx_ring[ring->queue_index] = NULL;
+               WRITE_ONCE(adapter->rx_ring[ring->queue_index], NULL);
 
        adapter->q_vector[v_idx] = NULL;
        napi_hash_del(&q_vector->napi);

diff --git a/drivers/net/ethernet/intel/ixgbe/ixgbe_main.c b/drivers/net/ethernet/intel/ixgbe/ixgbe_main.c
index f162b8b..97a423e 100644 (file)
--- a/drivers/net/ethernet/intel/ixgbe/ixgbe_main.c
+++ b/drivers/net/ethernet/intel/ixgbe/ixgbe_main.c
@@ -7051,7 +7051,10 @@ void ixgbe_update_stats(struct ixgbe_adapter *adapter)
        }
 
        for (i = 0; i < adapter->num_rx_queues; i++) {
-               struct ixgbe_ring *rx_ring = adapter->rx_ring[i];
+               struct ixgbe_ring *rx_ring = READ_ONCE(adapter->rx_ring[i]);
+
+               if (!rx_ring)
+                       continue;
                non_eop_descs += rx_ring->rx_stats.non_eop_descs;
                alloc_rx_page += rx_ring->rx_stats.alloc_rx_page;
                alloc_rx_page_failed += rx_ring->rx_stats.alloc_rx_page_failed;
@@ -7072,15 +7075,20 @@ void ixgbe_update_stats(struct ixgbe_adapter *adapter)
        packets = 0;
        /* gather some stats to the adapter struct that are per queue */
        for (i = 0; i < adapter->num_tx_queues; i++) {
-               struct ixgbe_ring *tx_ring = adapter->tx_ring[i];
+               struct ixgbe_ring *tx_ring = READ_ONCE(adapter->tx_ring[i]);
+
+               if (!tx_ring)
+                       continue;
                restart_queue += tx_ring->tx_stats.restart_queue;
                tx_busy += tx_ring->tx_stats.tx_busy;
                bytes += tx_ring->stats.bytes;
                packets += tx_ring->stats.packets;
        }
        for (i = 0; i < adapter->num_xdp_queues; i++) {
-               struct ixgbe_ring *xdp_ring = adapter->xdp_ring[i];
+               struct ixgbe_ring *xdp_ring = READ_ONCE(adapter->xdp_ring[i]);
 
+               if (!xdp_ring)
+                       continue;
                restart_queue += xdp_ring->tx_stats.restart_queue;
                tx_busy += xdp_ring->tx_stats.tx_busy;
                bytes += xdp_ring->stats.bytes;